Republican voters who cast their ballots in the last days of Oregon's primary -- following news stories about Monica Wehby's "stalking" incident -- were less likely to support her in Oregon's GOP Senate primary.

But voter returns show that Wehby's support levels dropped precipitously as elections workers counted mail ballots cast in the last few days of the election.

"It's a serious swing," said Bill Lunch, a retired political scientist at Oregon State University and analyst for Oregon Public Broadcasting, "and what it points to is that she'll have to address the concerns out there in a serious fashion."

As many as half of the Republican ballots were cast from Friday -- the day the revelations came out -- until the 8 p.m. Tuesday deadline, according to reports from the secretary of state's office.

Elections workers count ballots by starting with those cast first and working forward, so it's possible to get a sense of how voter behavior changed in the last days of the voting period. Unlike in almost all states, Oregon voters receive a mailed ballot and have just over two weeks to return them.

Among the ballots counted by 8:57 p.m. Tuesday, Wehby led Conger, 53.5 percent to 33.9 percent. Three other candidates split the remaining vote.

That may not seem like much. But between those two updates, about 90,000 more ballots were counted. And Wehby's lead in those votes was only about 1 percentage point.

All told, those 90,000 votes accounted for about 36 percent of the Republican ballots counted so far, so they appear to be those cast in the last days of the election.

Lunch said it was impossible to know how many of those late voters knew of the new revelations involving Wehby -- and to know how it affected their vote. The only way to determine that, he said, is with extensive exit polling, which did not appear to have been done.

On early Friday morning, Politico reported that Portland police were called by Wehby's ex-boyfriend, lumber executive Andrew Miller. He complained that Wehby had made several uninvited visits to his home and was "stalking" him and "harassing" his employees.

The report was quickly picked up by media sources in Oregon and in the rest of the country. Wehby, noting that no charges were ever filed against her, has repeatedly dismissed the revelations as irrelevant to the Senate race and represented an effort by Democratic operatives to divert voters from the real issues.